In 2013, a metal 3D-printing revolution is entering space. AMAZE is a recently announced project that aims to perfect the printing of space-quality metal components on Earth and beyond within five years. ESA (European Space Agency) and the EC (European Commission) have embarked on a project to perfect the printing of space-quality metal components. The AMAZE project involves 28 industrial partners across Europe. "We want to build the best quality metal products ever made," said David Jarvis, ESA's Head of New Materials and Energy Research, during a press conference at the London Science Museum on 15 Oct. 2013. Considered the third industrial revolution among manufacturers, 3D printing builds a solid object from a series of layers, each one printed on top of the last – also known as additive manufacturing. 1)

3D printing builds a solid object from a series of layers, each one printed on top of the last. This ‘additive manufacturing' technique produces very complex structures with minimal waste and maximum flexibility.

Never before have titanium structures been so flexible. Leaving traditional casting techniques aside, the AMAZE team printed its logo in titanium as an intricate net shaped to millimeter precision. The project is working with materials that can withstand temperatures up to 3500°C. 2)

The project envisages printing entire satellites and using the technology for missions to the Moon and Mars. With no need of launching heavy payloads, manufacturing in space could save huge amounts of time and money.

Figure 1: Photo of the AMAZE logo shown in the London Science Museum, UK, on October 15, 2013 (image credit: ESA)

To get to that future, ESA is looking at five metal additive manufacturing processes. "We are focusing on serious engineering components made of very high-tech alloys. We are using lasers, electron beams and even plasma to melt them," explains David. Some of the materials AMAZE works with only melt at 3500°C.

A quartet of pilot factories – each one employing different metallic 3D printing methods – are being set up in Germany, Italy, Norway and the UK. In parallel, a full industrial supply chain is being established for metallic 3D printing, incorporating feedstock alloys, printing equipment, finishing techniques, metrology and control software.

"We need high quality, we need it to be repeatable, and we need a supply chain. AMAZE connects all the key players within Europe and develops that supply chain," adds Jon Meyer, Additive Layer Manufacturing Research Team Leader at Airbus DS (former EADS Innovation Works).

As of November 2017, Europe's lead in metal 3D printing has been strengthened by the four-year AMAZE program, producing lighter, cheaper, organically shaped parts. ESA was among 26 academic and industrial partners developing novel processes and products for high-performance sectors. 3)

ESA helped to initiate the program, which was funded by the European Commission's FP7 (Seventh Framework Program) and coordinated by the UK's MTC (Manufacturing Technology Center) in Coventry. The Agency joined manufacturers Airbus DS and Thales Alenia Space in assessing prototype products for space use, while comparable end-users did the same for the automotive, aeronautics and nuclear fusion sectors. 4)

Objective: The overarching goal of AMAZE is to rapidly produce large defect-free additively-manufactured (AM) metallic components up to 2 m in size, ideally with close to zero waste, for use in the following high-tech sectors namely: aeronautics, space, automotive, nuclear fusion and tooling. Four pilot-scale industrial AM factories will be established and enhanced, thereby giving EU manufacturers and end-users a world-dominant position with respect to AM production of high-value.

Figure 2: Sun sensor and antenna support bracket produced through the AMAZE metal 3D printing program (image credit: Thales Alenia Space and Renishaw)

"The work of AMAZE ranges right across the process chain," explains David Wimpenny, Chief Technologist for the National Additive Manufacturing Center, based at the MTC. "It includes new approaches to part design, along with the challenge of reliably finishing and inspecting the resulting parts, introducing novel materials, improving production throughput and developing common industrial standards."

Figure 4: The 3D ‘additive manufacturing' process. Instead of standard ‘subtractive manufacturing' – where material is cut away from a single piece – additive manufacturing involves building up a part from a series of layers, each one printed on top of the other. It is the difference from digging out a bunker to building a house. The process starts with a CAD (Computer-Aided Design) model, which is then sliced horizontally apart to plan its layer-based physical construction. Anything suitable for the printing process can be designed by computer then printed as an actual item, typically by melting powder or wire materials, in plastic or metal (image credit: ESA)

To draw maximum benefit from the process, parts need to be designed specially. With 3D printing it is only the volume of material being fused together that is paid for, with no waste to be cut away, so the lighter the weight of the part the cheaper it ends up.

David Wimpenny adds: "It's really opened the eyes of designers: through 3D printing, complex, performance-optimized, lightweight parts actually end up costing less than traditional alternatives. During AMAZE we've been literally growing parts to bear the loads required; the result has been these organically shaped metal parts weighing less than half the of the original component, manufactured all in one – removing joints which represent potential points of weakness."

"This complexity means that file sizes can be huge – several orders of magnitude larger than a normal CAD file – and it can take a long while to process all that data. But another AMAZE development has been new software tools to radically reduce the time involved."

Figure 5: Among the largest items produced by AMAZE, this 3 m diameter structural cylinder was printed in titanium alloy Ti64 using 'directed energy deposition' melting powder with a laser (image credit: ESA and IREPA)

New materials were developed to meet specific industrial needs, including the first 3D printing of InVar, an alloy of nickel and iron that is highly prized by the space sector for its ability to withstand orbital temperature extremes without expansion or contraction.

3D printing of vanadium and tungsten was also demonstrated. These high-melting point metals are suited for use within nuclear fusion reactors as well as rocket engines.

Assessing a range of different 3D printing techniques, the variety of produced parts varied hugely, from millimeter-scale samples to meter-scale structural items. "Just as important was increasing the speed and productivity of the process, from a few hundred grams to kilograms per hour, without compromising quality," explains David Wimpenny. "We achieved this in various ways, including increasing the number and power of the lasers used for material melting."

"We've also worked to ensure the powder feedstock is optimized for the process. The powder particles have to have the correct size and shape to provide the right flow properties to give consistently high-quality, defect-free layers."

Another challenge was the post processing, finish and inspection of the parts, including standardized non-destructive test procedures. Medical-style 3D CT (Computed Tomography) scanning is one solution that was explored, with AMAZE findings going towards an ongoing effort to develop a common ISO standard for the field.

"The industrial partners in the project are now commercializing the results of the project and the AMAZE experience has helped to forge a research community which will continue to increase the knowledge and improve the capability of additive manufacturing processes going forwards", says David Wimpenny.

For instance, Norsk Titanium – supported by developments made during AMAZE – has become the first company to manufacture structural aircraft components using metal 3D printing.

Tommaso explains that the ESA–RAL Advanced Manufacturing Lab at Harwell in the UK, has played an important role in assessing the performance of AMAZE's aeronautical and space outputs: "It has helped to define verification strategies used for critical applications, putting them on a fast track for adoption by projects."

The information compiled and edited in this article was provided byHerbert J. Kramer from his documentation of: "Observation of the Earth and Its Environment: Survey of Missions and Sensors" (Springer Verlag) as well as many other sources after the publication of the 4th edition in 2002. - Comments and corrections to this article are always welcome for further updates (herb.kramer@gmx.net).